Extrusion device



Fb.17,1942. E', ROTH 2,273,595

EXTRUS'ION DEVICE Ti E. mi

,man

lNVENTOR l l f ERNEST J. ROTH ATTORNEY Feb. 17, 1942. E J, RQTH 2,273,595 I ExTRUs 10N DEVICE Filed June 2l, 1941 4 Sheets-Sheet 2 5 lNvl-:NroR

J3 v ERNEST J, ROTH WMM.

ATTQRNEY Feb. 17, 1942.Y E. J. ROTH ExTRUSIoN DEVICE Filed June 2l. 1941 4 Sheets-Sheet 3 INVENTOR ERNEST J. ROTH ATTORNEY Feb. 17, 1942.

E; J. ROTH EXTRUSION DEVICE Filed June 2l, 1941 4 Sheets-Sheet 4 fs s \B q Q R m QPQW INVENTOR ERNEST J. ROTH ma m ATTORNEY i PatentednFeb., 17, 1942 EX'rnUsIoN DEVICE Ernest J. Roth, Norwood, N. J., assignor to Joe Lowe Corporation, New York, N. Y., a corpora.-

tion of Delaware Application June 21, 1941, Serial N0.`399,061

5 claims. (cn iov-14) This invention relates to improvements in .ex-. 'l

trusion devices, and more particularly to extrusion machines of the die expressing type of the character disclosed generally in my application s. N. 368,797, med Decemer s, 1940, now Patent' Number 2,246,758, issued June 24, 1941, of which the present application is a continuation in part. The invention is particularly applicable for use in the extrusion of plastic formations vof edible productssuch as raw doughnuts `made from bat- The principal object of this invention is to reduce agitation vof the plastic material during its passage through the machine, to a minimumf thus reduction working of the plastic material, so as to avoid toughening of the finished product.

Another object is to 'insure unformity of size vof the extrusions.V

Another object is an extrusion machine which is positive in operation.

Another object is anextrusion machine which is easy to regulate to effect a positive, instantaneous, and accurate variation, in the size of the Other objects will appear from the following detailed description.

In accordance with this invention the plastic material is deposited in a hopper open to atmcsphere at vthe top, said hopper having an intermlttently valved connection with an intermitt'ently vented extrusion outlet, so that when the valve connection to the hopper is opened, the plastic-material flows under the influence of gravity through the( open valve in the direction of the extrusion outlet whereupon the valve closes to cut off communication with the hopper; the pressure belowthe said valve is rapidly built vup to a value substantially above atmosphere while the extrusion culet is opened toexpel some of the plastic material through said extrusion outlet and the extrusion outlet is then closed to sever the extrudedplastic; the pressure below the lvalve is reduced to atmosphere before said valve is again opened to permit more dough to ow from the hopper The size of the extrusion may be controlled in a very positive manner, regardless of the viscosity of the plastic, by regulating the degree of air pressure'within the extrusion device.

In the drawings comprising four `sheets of nine figures numbered' Figs. 1 to 9 inclusive;

Fig. 1 is a View of one side of the extrusion Y machine and includes a power unit associated therewith, all assembled in operating position upon an automatic doughnut machine;

Fig. 2 is a view of the opposite side of paratus assembly of Fig. 1;

Fig. 3 is a vertical cross section of the exthe aptrusion machine feed unit, with some of they parts partially broken away;

Fig. 4 is a top plan view on the dough chamber of the feed unit of Fig. 3, with the hopper base plate removed; l

Figs. 5 and 6 are side views, partly in crcss section, of the intermittently Vented extrusion outy let and its associated clutch mechanism, showing the sleeve cutter and forming die in different positions;

Fig. 'lis a diagrammatic view of the pump and piping system of the power unit; and

Figs. 8 and 9 are `omparative diagrams showing the operation of the extrusion machine feed unit during two different stages of the operating cycle. A

Like reference characters designate corresponding parts throughout the several figures of the drawings.

The extrusion machine consists. essentially of: a feed unit (Fig. 3) having a feed hopper 20 for receiving plastic material, a slide valve 30 for controlling the -ow of the plastic downwards by gravity from the hopper 20 into the chamber formed by the lower casting 4I, and an intermittently vented extrusion outlet consisting of sleeve 5I (Figs. 5 and 6), through which the plastic is extruded under pressure over a forming die 54 which imparts the desired shape to the plastic. the plastic forma-1 ion being thereafter severed and released by the action of the sleeve cutter or cutting die 52; in combination with a power and control unit (Figs. Land 2), for opening and closing the slide valve 30 and the cutting die 52 of the extrusion outlet in properly timed sequence, said power and control unit including a compressed air pump, and'means for driving the pump and control. unit; and the necessary connecting rod and air pipe connections, for combining the power and control unit, with the slide valve, with the extrusion outlet, and with the air chamber 29, respectively, of the feed unit.

The lower end of the hopper 20 is welded in the opening formed in a base plate 22. Plate 22 is detachably secured 'to the upper face of the upper casting 2,6, rtv means of a series of knurled bolts 2|, which screw into the bronze bushings 25 embedded in the holed ange 24 of upper casting 26. A gasket 23 is clamped between hopper base plate 22 and thel upper face of upper casting 26, to provide an air-tight fit. A seriesfof partition walls 28 separate upper casting 26 into an inner compartment, and an air chamber 29, surrounding said inner compartment. 'I'he partition walls 28 of the inner compartment are vconnected to the outer wall of upper casting 26 by a series of vertical webs 33-33', by the horizontal baille plate |52, and by the vertical webs forming vthe baille plates 34- 34. The upper face ofthe' webs 33t-33 and of the baille plates 34-34 are not flush with the upper face of the partition walls 28--28, but terminate slightly below the face of the partition walls 28-28 to define air passages for connectinggthe various compartments of air chamber 29 together.

Upper casting 26 registers with tne lower casting 4|, the flanges 2l of the upper casting nest- ,ing in the flanges 41 of .the lower casting, and

the two castings being clamped together by a series of machine screws 48-48 (Fig. 3). The

.said extrusion nozzle which extends downwards to form an inner sleeve 5| which is outwardly bevelled at its lower extremity. A sleeve cutter 52 (Fig. 5) is slidably mounted upon inner sleeve 5|, the lower edge of sleeve Vcutter 52 being bevelled at 53 to form a relatively thin cutting edge. A forming .die 54 having a downwardly and outwardlybevelled edge is mounted upon a stem 55 which is malethreaded at the upper end to register in the female threaded opening of a spider 56 forming a part of the casting of inner sleeve 5|. The forming die 54 is positioned in spaced relation to the lower extremity of inner sleeve 5|, so that the plastic material extruded through the extrusion nozzle flows over the forming die 54 to form a plastic formation having holed ears 49 of flange 4l are used tosecure the feed unit to a supporting bracket |53 (Fig. 2) by means of a series of knurled bolts ||8. The lower casting 4| is subdivided by means of a series of partition walls 42-42 into an inner chamber and an outer chamber; the partition walls 42-42 being securedto the walls of lower casting 4| by means f webs generally similar to the webs 33-33 (Fig. 4) of upper casting 26. The partition walls 42--42 offlower casting 4| register with the Apartition walls 28-28 of upper casting 26. Oppositely disposed rabbeted bronze inserts are embedded in the adjacent lower`and upper face of partition walls 28 and 42, to jointly define a guide channe1 for the knife blade 30 (Figs. 3 and 4). Knife blade 30 operates back and forth in the guide channel 3| formed by the bronze inserts, to connect the hopper 20 with, and disconnect hopper 26 from, the chamber formed by lower casting 4| wherein the plastic material 58 (Fig. 9) is housed. The baille plate |52 (Fig. 4) prevents any plastic materialadhering to the knife blade from working its way upwards between the baffle plates 34-34 into the air port 35. The inwardly disposed faces of the baiile plates |52 are provided with two or more V shaped slots 36-36 which trap any plastic adhering to the face of knife blade slide valve 39, and the plastic thus ltrapped effectively seals the knife blade opening against any leakage between air chamber 29 and atmosphere.

Slide valve 36 is actuated by a bifurcated lever arm 40 having two pairs of bifurcated fingers 39-39. An actuating pin 3l secured to the outer end of slide valve 36 by means oi the machine screws 36-38, is cradled between the pairs of bifurcated fingers 39 of the lbifurcated lever arm 40, so that when the lever arm 49 is rocked upon its drive shaft HZ-(Fig. 2), a reciprocating slidingmovement is imparted to the slide valve 30.' 'Ihe wal1 of upper casting 26 is drilled and tapped to form an airport (Fig.

an opening therein conforming in contour to the contour of the forming die. When the apparatus is used in making doughnuts the forming die 54 may be disc shaped, so as to mold the batter in annular form. The internal diameter of sleeve cutter 52 is slightly larger than the over all diameter of inner sleeve 5| and forming die 54. so that sleeve cutterl 52 will slide telescopically relative to inner sleeve 5| and forming die 54 with a snug t (compare Figs. 5, 6, 8, and 9).

Each cutting sleeve 52 terminates at its upper end in a shoulder including an annular channel 5'! wherein the lifting pins 60-69 of a lifting fork (Fig. 5) normally engage to control the telescopic action of thesleeve cutter 52 on inner sleeve 5|. Each sleeve cutter 52 is separately operated by its associated but independent lifting fork 6|, said forks being freely pivotally mounted upon one common rocking shaft 62. Each lifting fork 6| is provided with separate clutch mechanism (Figs. 5 and 6), so that the operation of each sleeve cutter 52 and its associated forming die 54 can be independently controlled, to selectively operate any one or more of the forming and cutting dies as desired.

Each clutch mechanism (Figs. 5 and 6) consists of two distinct elements namely: a clutch 15, and a clutch pin 69. The forks 6|, and their respective clutches and clutch pins, are all mounted upon one common rocking shaft 62, the hubs of the housings 1| being keyed to the shaft62, while each clutch 'l5 and its associated fork 6| is freely pivotally mounted upon the rocking shaft 62, and is provided with an adjustable connection l2 between fork 6| and its clutch l5, to permit adjustment of sleeve cutter 52 relative to its asso-y ciated forming die 54. Referring to Figs. 5 and 6, clutch pin 69 is slldably mounted in a hollow cylinder forming a housing 11|. A coiled sp g 19 is mounted upon pin 69 between the-hea 80 of .the pin and the shoulder of the housing 1|. A

locking pin Ill (Fig. 6) slides in a slot in the wall of the housing, but-by pulling clutch knob 68 outwards until locking pin 10 of clutch pin 69 clears the said# slot, the knob 68 may be ro-` tated until locking pin 'l0 engages in notches cut in the shoulder of housing 1u/to retain clutch neath the frying kettle. The control unit includes engaged position the -head 80 of clutch pin 69 registers in a socket 8| formed in clutch 15,'and in this position clutch -pin,69 and clutch 15 rock together upon rocking'shaft 62 to rock lifting fork 5 6|, thus raising and lowering the bevelled edge .53 of sleeve cutter 52 past the bevelled edge of forming die 54. Anadjustable stop 16 engages la safety stop bar 18 to limit the forward move- -ment of clutch 15 when clutch pin 69 is disen- 10 gaged from clutch 15 (Fig. 5), whereby the forward movement of clutch 15, and therefore of lifting fork 6|, is'l arrested, thus preventing fork 6| from rocking about shaft 62 to such an'angle as to disengage the lifting pins lili-60 from the 15 annular channel 51 of the shoulder of sleeve 'cutter 52, thereby preventing-sleeve cutter 52 from being released and falling .offinner sleeve into frying kettle-y ||1 (Fig. 1). .'A hexagonheaded edadjusting pin 12 to secure pin 12 andclutch together. Adjusting pin 12 also passes. through an opening in a cross pin 61 which is journalled in the bifurcate'd ears '14 formed at the outer end upon the threaded adjusting pin 12, the. size of ythe opening between the bevelled edge'53 of sleeve cutter 52 and forming die 54 may be regulated. Each lifting fork `6| can thus be independently 30 69 are engaged in the sockets 8| of their re- 35 l spective clutches 15, while to reduce thedelivery capacity of the extrusion machine one or more clutch pins 69 is di 'ngaged (Fig. 5) .from the socket 8| of its clutc 15.

The operation of the extrusion machine feed unit (Figs. 3 to 5) is controlled by a control unit (Figs. 1 and 2), positioned beneath* `the frying kettle ||1. The various elements of the control unit may be mounted in any suitable manner beshown) mounted inlthe gear reduction box 94. 5.5 Cam follower 89 (Fig. 2) mounted on one end of bell lcrank lever 86 follows box cam 492 to rock lever-arm 82 via connectingrod 84, thus controlling the telescopic action ofthe sleeve cutter 'szs2 (Figs. 5 and s); while cam `f011pwer los 60 (Fig. l) mounted upon. one end vof bell crank lever |09, follows box cam |03` to rock bifurcated lever arm 40 (Fig. 2) thus controlling the back and forth motionof the knife blade slide valve 30 (Fig. 3). In -the position of cam follower 89 65 as shown in Fig.v 2, the sleeve cutters 52-52 (Figs. 5 and 8) would be closed by way of bell crank lever 86, crank pin 85, connecting rod 84,

lever pin 83, lever arm 82, clutch sha t 62, clutch pin housing 1|, clutch pin'69, `clut fork 6|, lifting p ins 60-60, and Ysleeve'cutter 52. When by the rotation of box cam 92, cam follower 89 passes through the flat V. shaped portion 93 of the bcx cam, bell crank'levei` 86 rocks to control the up'and 'down' telescopic action ofthe 75 pump |2I. of. lifting -fork 6|, and by varyingthe position of 25 the lower and upper adjusting nuts 66 and 13 the pulley 95.

tions to vary the position of the V shaped drive belt 96 in pulley |01, thus varying the 'speed of 15, uiting 7o three-way valvegl 29.

s1eeve cutter sas-sz. with cam followerv los in the position shown in 'Fig. 1, knife blade slide valve 301s open (Fig. 4), but as shaft |31 (Fig. 1)

continues to rotate, cam follower |08 enters the semicircular portion of box cam |03, thus rocking bell crank lever |09, crank pin ||0, connecting rod lever arm 40, and actuating pin 31 (Fig.

4), of knife blade slide valve 30,`to close the knife -4 blade slide valve.

Pressure pump |2| (Figs. 1 and '1) which is connected .to themaln shaft |54 of gear reduction box 94, delivers compressed Iair through its pressure port |25 to compressed air line |05, Oil for Y pump |2| -is supplied froma drip oil cup |04 (Figs.

1, 2, and '1). The intake port. |26 of pump |2| is connected to atmosphere byway of an open ended perforated lintake |02. Intake |02 has an'- open mouth, so that if the perforations are accidentally covered up, said open mouth will prevent pivot bolt passes through the ear 64 of thread- 20 any sealing up of the intake side of the pump, and the intake |02 is perforated so that if its open mouth is accidentally Vplugged the perforations willstill admit air tothe intake side |26 of Compressedgair line |05 (Fig. 7) is connected through an oil trap |06 and comu pressed air line, |28 to a three-way valve |29. A

baille plate |21 is inserted in oil trap |06 to pre- -vent any drops of oil carried into compressed air -pipe |05 by n'the rotation of pressure pump 2| from entering compressed air line |28, orany part of the pneumatic system |therebeyond, such as the three-Way valve |29. A pet cock |01 is4 used for periodically draining trapped oil from oil trap |06. The degree of pressure in the pneumatic system is regulated by a regulating valve |23 whichis controlled by a regulating knob H9 which connects with the valve |23 by means of a flexible cable |22,any excess pressure being vented at exhaust port |24.

doughnut frying kettle I1 so that the formations of plastic material 59 (Fig. 9) which are made of doughnut batter will fall into the frying kettle and will be conveyed. through the frying kettle by means -of a travelling conveyor (not shown) during the cooking operation.v- The travelling conveyor is operated by suitable gears and sprockets' which are driven by the conveyor drive chain The speed of the lpulley 95 of gear reduction box 94 may bevaried by turning worm screw control 99, thus operating the worm screw 91 which passes through the threaded ears 98 of the motor base to move motor |00 towards and away from 'I'he adjustable pulley |0| funcpulley and of gear reductionbox 94,.

The compressed air pipe |28 is conn cted to the air chamber 29 (Fig. 3) of the feed unit by means of the nipple 5 (Fig. 8). The endsjof v a flexible hose ||4 are respectively connected by means of hose couplings `H8 to vthe nipple ||5 (Fig. 1) and to the delivery port m (Fig. '1) of I' The pressure valuein the flexible hose ||4 is indicated by the pressure sure inlet |35 and compressed air line |28 in one position of the three-way valve; and then with exhaust port |36 and exhaust nipple |38 in the alternate position of the three-way valve. Any suitable form of three-way valve timed to operate in proper sequence with slide valve 30 and sleeve cutters 52-52, may be used for this purpose. In the drawings the mechanism for actuating the three-way valve consists of a solenoid |30, having valve plungers |4| and |42, mechanically coupled to suitable operating levers pivotally connected to a rod |40 which forms an extension of the solenoid plunger |32. In the position shown in Fig.\7 the solenoid is deenergized, and its plunger |32 has fallen under the inuence of gravity to the release position. In the release position of plunger |32, valve plunger |4| seals pressure inlet |35 and disconnects compressed air line-|28 4from flexible hose ||4; at the same time valve plunger |42 opens the valve of exhaust port |36 thus connecting flexible hose ||4 to atmosphere at exhaust nipple |38. Under these conditions the air pressure in chamber 29 of the fee'd unit is' reduced to atmosphere, and any plastic material 58 (Fig. 8) entering lower casting 4|, 'displaces its own volume of air from air chamber 29 through nipple |5,A flexible hose ||4, and exhaust nipple |38, to atmosphere.

. 'I'he solenoid |30 is energized over an operating circuit-including the interrupter ring |44 which is mounted upon the cam shaft |31, to rotate in synchronism with box cams 92 and |03. Inter' rpter ring |44 includes a metallic segment and' 'an insulated segment |46. The metallic segment is grounded by way of ground lead |45. A battery, or other suitable source of electric current, such as thegenerator |5| may be employed 'to supply electrical energy to the solenoid circuit.

The circuit may include a suitable resistance coil |48. The solenoid circuit is interrupted at interrupter brush |41 whenever the Iinsulated segment |46 passes under the brush. When brush |41 is in contact with the metal segment lead |45, thus closing the circuitto energize solenoid |30. When the solenoid is energized its plunger |32 is drawn upwards into contact with o pole piece |3| thus lifting rod |40, thus closing the valve controlled by valve plunger |42; and disconnecting exible hose |4 and air chamber 29 from atmosphere while at the same time opening the'valve controlled by valve plunger I4| thus connecting compressed air supplied by pump |2| overair line |28 to flexible hose ||4 and to air chamber 29 of the feed unit. Solenoid, |30 remains energized, supplying compressed air to chamber 29, so long as interrupter brush |41 is in contact with the metal segment ofsinterrupter ring |44, but when the interrupter ring rotates to bring the insulated segmenty |46 into contact .with the brush |41, the operating circuit for the air in air chamber 29 due to the constant action of pump` |2| and of three-way valve |29, tends to keep the walls 28 and 42 of the inner chamber cool at all times, thus keeping the plastic material at a relatively lower temperature than would otherwise be the case. f

The lower face of the hopper base plate 22, and the upper face of upper casting 26, are both recessed to receive the gasket 23. Gasket 23 may be made of any suitable resilient material, but a gasket made of neoprene gives good results. The thickness of the gasket is such that when th'e gasket connection is completely air tight the 1ow er face of base plate 22 will still be separated from the upper face of upper-casting 26. Gasket 23 may be permanently cemented in the recess in base plate 22 with a suitable cement. 'I'he electro-mechanical valve |29 may be replaced by a mechanically operated three-way valve, -in which case the interrupter ring |44 and its associated electrical circuit including solenoid |30, would be replaced by suitable cam mechanism, and by and lever mechanism for-mechanically coupling the cam mechanism to the three-way valve. One suitable form of mechanically operated valve is disclosed in my U. S. Patent; 2,246,758.

into hopper 20. As cam shaft |31 rotates'cam follower |08 (Fig. I) enters the eccentric segment of box cam |03 and knife blade slide valve 30 starts to open to establishla continuous passage between hopper 20, extrusion outlet 4'3 and inner sleeve 5|. When camfollower |08 reaches the top portion of the eccentric segment of box cam |03 (Fig. I), knife blade slide valve 3|! is fully open, and dough. flows downwards through the open slide valve 301:0 ll lower casting 4| with dough. Any air displaced by the dough is forced out of air chamber 29, along nipple ||5,

flexible hose ||4, through' three-way valve |29 which isreleased, and exhaust nipple |38, to atm'osphere. During this feed stroke: interrupter brush |41 is in contact with the insulated segment |46 of interrupter ring |44 thus opening the circuit of solenoid |30' (Fig ."1) to release plunger |32 and rod |40 whereby compressed air line |28is sealed by valve plunger |4|and valve plunger |42 is openedto connect delivery port |43 to atmosphere at exhaust nipple |38; cam follower |08 Pis. traversing the eccentric portion of'box cam |03 to open knife blade |30; and cam follower 89 (Fig. 2)' is traversing the circular portion of box cam 92 to hold the sleeve cutters 52 in the position shown in Fig. 8, thus closing the extrusion outlets.

Extrusion stroke The continued (clockwise) rotation of cam shaft A.|31 causes cam follower |08 to enter the circular segment of box cam |03 (Fig. 7) whereupon knife blade slide valve 30 is closed (Fig. 9) to disconnect hopper 20 from lower casting 4|. As cam shaft |31 continues to rotate the metal segment of interrupterfring |44 makes contact with interrupter brush |41 tovclose the energizing circuit for solenoid |30, thus connecting compressed air line |28 to exible hose ||4 and to air chamber 29, to build up the pressure in air chamber 29 to the desired value. As cam shaft |31 continues to rotate cam follower 89 (Fig. 2`) enters the-nattened V segment 93 of box cam and the cycle of operation is repeated.

I l. In an extrusion machine an 32 -to cause the sleeve cutters 52 to b e drawn-upl wards on their associated inner sleeves 5|, thus opening the extrusion outlets and extruding the formation of plastic material 59 (Fig. 9). AThe continued rotation of cam shaft |3'| returns cam 5 follower 88 to the circular segment of box cam 92- whereupon the sleeve cutters '52 move downwards (Fig. 8) to close the extrusion nozzles, and as the bevelled edge 53 of each' sleeve cutter passes around and beyond the bevelled edge of v10 its forming die 54 it severs and releases the extruded formation of plastic material 59 which falls into the pocket of the travelling conveyor immediately beneath forming die 54. The movement of the travelling conveyor carries the vplas-r ticformation through the'frying kettle H1,"

Where, in the system illustrated, itis fried to produce a doughnut." rI h'e continued rotation of camshaft |31 brings the insulated segment las of interrupter ringiM into contact'with brush 20 |41 to open the energizing circuit forsolenoid The size of 'the plastic extrusion'58 can vbe regulated' immediately and within very critical)- limitsby operating regulating knob' I I9 to increase or decrease the pressure in compressed air line |85 and consequently 1n flexible hose ||4 and air chamber 29.

What is claimed ist d in combination, a chamber for housing plastic material,-

- 40 said chamber having a valved inlet through Y which plastic may be admitted into, and a valved I outlet throughv which plastic may' be extruded out of, said chamber, apump for supplying compressed air to said chamber when the inlet valve is closed and the outlet valve is open to extrude plastic from said chamber, an exhaust port for venting said chamber to atmosphere, a threeway valve operable to intermittently disconnect. said pump from said chamber and connect said 5-0 chamber with the exhaust port to equalize the pressure in said chamber with atmosphere before theinlet port opens to admit plastic into thechamber,I to disconnect said exhaust port from said chamber after the inlet port closes. and then to connect said pump to said chamber to rapidly build up the pressure within the chamber substantially above atmospherebefore the outlet valve opens to -allow plastic to be extruded through said extrusion outlet, and means for opening and closing said inlet and outlet valves and for operating said three-way valve in properly timedsequence. r

2. In an extrusion machine and in combination, a chamber for housing plastic material. said chamber having avalved inlet through which plastic may be admitted into, and avalved outlet through which plastic may be extruded out of, said chamber, a pump for supplying com- L pressed air to said chamber when the inlet-valve is closed and the outlet valve is open to extrude plastic from said chamber. an exhaust portlfor venting vsaid chamber to atmosphere.. a threeway valve operable to intermittently disconnect saidpump from said chamber and connect said ing plastic material, a valved inlet through which chamber withthe exhaust' port to equalizethe pressure in said chamber with atmosphere before the inlet port opens to admit plastic into the chamber, to disconnectsaid exhaust port from said chamber after the inlet port closes, and then to connect saidpump to said chamberv to rapidlyA build up the pressure within the chamber substantially above atmosphere before the outlet -valve opens to -allow plastic .'to be V'extruded through said extrusion outlet, means for opening andclosing said inletand outlet valves and for operating s aid three-Way valve in properly' said chamber having a valved inlet through which plastic may be admitted into, anda valved outlet through which plastic may be extruded out of, said chamber, a pump for` supplying corni pressed air tov said'chamber, an exhaust port for venting said chamber to atmosphere,- an elec tro-magnetic three-'way valve, said three-wayvalve being operable, to intermittently disconn ect said pump from said chamber and connect .said chamber with said exhaust vport to vent said chamber to atmosphere before the inlet valve opens to admit Iplastic into said chamber, to disconnect said exhaustA port from said chamber 4after Ithe inlet valve closes, and then to vconnect said, pump4 to said chamber. to rapidly build up `pressure within the chamber substantially'above atmosphere before the outlet valve opens to allow plastic to be extruded therethrough, an electrical` control circuitk for .said electro-magnet,

said control circuit being operable'to actuate said electro-magnet to operate said three-way valve, and means for opening and closing said inlet-and outlet valves andsaid control circuit in properly timed sequence.

4. In an extrusion machine and. in-combinaJ- tion, a chamberfor housing plastic material, said chamber having a valved inletthrou'gh winch plastic may be admitted into, and 'a valved outlet through which plastic may be extruded` I A out of, said chamber, a pump for supplying compressed air to said chamber, an lexhaust port for venting said chamber to atmosphere, an electro-magnetic three-way valve,. said three-way valvebeingoperable, to intermittently discon-l neet said pump from said chamber and connect said chamber withsaid exhaust port to vent said chamberv to atmosphere before the inlet valve opens to admit plastid into said-chamber',

to disconnect said exhaust port from said chamber after the inlet valve closes, and then to connectsaid pump to said chamber torapidly build up pressure within the chamber substantiallyi above atmosphere before the outlet valve ozpens to allow plastic tobe extruded therethrough, an

electrical control circuitfor said electro-magnet, said control'circuit beingv operable to actuate.

said electro-magnet to operate said three-.way

valve, means for 'opening and closing said inlet i and outlet valves and said` contr'ol circuit in operly timed sequence, andmeans for regu'v .,mag'netand said interrupter, c said cam mechanism, three-way valve, and the` "plastic 'may beadmitted into saidchamber, a

valved outlet through which plastic may belextruded v from said chamber; a control unit separate and distinct from the'.feed unit, said control unii-I comprising, a pump, a three-way valve connected to said pump, an electro-magnet for operating said three-way valve, a circuit ln- `terrupter, .a wiring circuit inclu g said electromechanism,

.wiringfcircuit of said electro-magnet, being respectively adapted', to be mechanically. prie/L11` matically, and electrically'connected tothe inlet v tic formations from the feed unit chamber, and

the Periodic severance of the plastic extrusions thus-formed. v

ERNEST J. ROTH. 

